Contrary to the rumblings of the undead, Lord Keynes was never a raving lefty. He dismissed Karl Marx, had no time for the "labor theory of value," left plenty of room for "the market," and found the bourgeoisie far more enticing than the working class. Nor do his ideas necessarily lean to either right or left. Deficit financing, the major tool of Keynesian economics, has been used in the United States less to fund welfare programs than to pay for World War II, the military-industrial complex, and the wars in Vietnam and Iraq, while Hitler did not need Keynes to use deficits in Germany to grow the Third Reich out of the Great Depression. On its own, the approach does not solve structural problems in the economy, whether caused by business, labor, or misplaced regulators, and does not tell us how to create self-sustaining growth that will preserve the planet. All that said, Keynes and Krugman do point us toward the beginning of a rational economic policy. The rule of thumb is simple. When times are tough and the private sector pulls back, borrow or print money to stimulate demand. When growth returns, pay down the borrowing, an essential follow-through for both Keynes and Krugman. Timing is crucial, and now is the time to spend to promote growth, not to cut back in the name of austerity.

In a way, Krugman has already won the argument. Berkeley's Brad deLong and Harvard's Larry Summers, who was Obama's chief economic advisor, used mathematics to explain "Fiscal Policy in a Depressed Economy." Top economists at the IMF performed their own math exercise, which led managing director Christine Lagarde and European officials to begin moving to loosen fiscal targets for troubled economies and to give Portugal and Italy an additional seven years to pay back their bailout loans. The IMF has also warned British Chancellor George Osborne that he is "playing with fire" by pursuing austerity too aggressively. As for Obama, he has always understood the need for federal spending to stimulate the economy, even if he is now agreeing to cut Social Security and increase Medicare payments as part of "a grand bargain" to trim the deficit - or as Professor Bill Black calls it, "the grand betrayal."

And just this week, one of the leading arguments for austerity and against stimulus - Carmen Reinhart and Kenneth Rogoff's "Growth in a Time of Debt" - was found to have a major spreadsheet error and some questionable statistical techniques.

Intellectually, this is where the great debate now stands, especially in Europe. As London's "Financial Times" editorialized last week, "It is increasingly clear to the Eurozone core that there is only so much left to squeeze from the periphery." But politically, no one with any power - not even French President François Hollande, who taught economics at his country's top graduate schools - has stepped forward to carry Krugman's winning argument to its obvious conclusion. Why not join together in all of the troubled economies to throw off the suicidal austerity and move stimulus into high gear? Why not indeed?